School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
School of Chemical and Physical Sciences, Victoria University of Wellington, PO Box 600, Wellington, New Zealand; Centre for Biodiscovery, Victoria University of Wellington, PO Box 600, Wellington, New Zealand.
Bioorg Chem. 2023 Apr;133:106345. doi: 10.1016/j.bioorg.2023.106345. Epub 2023 Jan 11.
Many studies have investigated the Mincle-mediated agonist activity of α,α'-trehalose-6,6́-glycolipids, however, none have considered how the position, or absence, of the ester moiety influences Mincle-mediated agonist activity. We prepared a variety of 6-C-linked α,α'-trehalose glycolipids containing inverted esters, ketone, carboxy or no carbonyl moieties. Modelling studies indicated that these derivatives bind to the CRD of Mincle in a manner similar to that of the prototypical Mincle agonist, trehalose dibehenate (TDB), with NFAT-GFP reporter cell assays confirming that all compounds, apart from derivatives with short alkyl chains, led to robust Mincle signalling. It was also observed that a carbonyl moiety was needed for good Mincle-mediated signalling. The ability of the compounds to induce mIL-1 β and mIL-6 production by bone marrow-derived macrophages (BMDMs) further demonstrated the agonist activity of the compounds, with the presence of a carbonyl moiety and longer lipid chains augmenting cytokine production. Notably, a C20 inverted ester led to levels of mIL-1β that were significantly greater than those induced by TDB. The same C20 inverted ester also led to a significant increase in hIL-1β and hIL-6 by human monocytes, and exhibited no toxicity, as demonstrated using BMDMs in an in vitro Sytox Green assay. The ability of the inverted ester to enhance antigen-mediated immune responses was then determined. In these studies, the inverted ester was found to augment the OVA-specific Th1/Th7 immune response in vitro, and exhibit adjuvanticity that was better than that of TDB in vivo, as evidenced by a significant increase in IgG antibodies for the inverted ester but not TDB when using OVA as a model antigen.
许多研究都探讨了 Mincle 介导的 α,α'-海藻糖-6,6'-二醇脂质激动剂活性，然而，目前尚无研究考虑酯基的位置或缺失如何影响 Mincle 介导的激动剂活性。我们制备了多种含有反式酯、酮、羧基或无羰基的 6-C 连接的 α,α'-海藻糖糖脂。建模研究表明，这些衍生物与 Mincle 的 CRD 结合的方式与原型 Mincle 激动剂海藻糖二庚酸酯（TDB）相似，NFAT-GFP 报告细胞测定证实，除了具有短烷基链的衍生物外，所有化合物都导致了强烈的 Mincle 信号传导。还观察到羰基是良好的 Mincle 介导信号传导所必需的。化合物诱导骨髓来源的巨噬细胞（BMDM）产生 mIL-1β和 mIL-6 的能力进一步证明了化合物的激动剂活性，其中羰基和较长的脂质链的存在增强了细胞因子的产生。值得注意的是，C20 反式酯导致的 mIL-1β 水平明显高于 TDB 诱导的水平。同样的 C20 反式酯也导致人单核细胞中 hIL-1β 和 hIL-6 的显著增加，并且在体外 Sytox Green 测定中使用 BMDM 证明没有毒性。然后确定了反式酯增强抗原介导的免疫反应的能力。在这些研究中，发现反式酯在体外增强了 OVA 特异性 Th1/Th7 免疫反应，并表现出优于 TDB 的体内佐剂活性，这表现在使用 OVA 作为模型抗原时，反式酯而非 TDB 显著增加了 IgG 抗体。
